Method of producing continuous filaments using a rotating heat-extracting member

ABSTRACT

A method of stabilizing the release point of a filamentary product formed from the melt on a rotating heat-extracting member by applying a tension force to the filament subsequent to its release from the rotating member with the tension force of a magnitude to override variations in the adhesion of the filament to the rotating member. The filament is necessarily supported between the release point and the means used to generate the tension force in the filament.

United States Patent 11 1 Stewart et al.

[ METHOD OF PRODUCING CONTINUOUS FILAMENTS USING A ROTATINGHEAT-EXTRACTING MEMBER Inventors: Oliver M. Stewart, Columbus;

Robert E. Maringer, Worthington; Carroll E. Mobley, Jr., Columbus, allof Ohio Battelle Development Corporation, Columbus, Ohio Filed: Jan. 30,1973 Appl. No.: 328,121

Assignee:

[1.5. CI 164/87, 264/332, 264/164, 264/165, 164/282 Int. Cl B2211 11/06Field of Search 164/82, 87, 276, 282; 8 264/164, 165, 176 F, 332

. References Cited UNITED STATES PATENTS ,Cole .1 164/276 [451 May 28,1974 4/1911 Staples 164/276 989,075 3,548,581 12/1970 Bobkowicz etal.... 264/176 F 3,710,842 1/1973 Mobley et a1 164/87 PrimaryExaminer-R. Spencer Annear Attorney, Agent, or FirmStephen L. Peterson[5 7 ABSTRACT A method of stabilizing the release point of a filamentaryproduct formed from the melt on a rotating heatextracting member byapplying a tension force to the filament subsequent to its release fromthe rotating member with the tension force of a magnitude to overridevariations in the adhesion of the filament to the rotating member. Thefilament is necessarily supported between the release point and themeans used to generate thetension force in the filament.

12 Claims, 4 Drawing Figures PATENTEB m 28 m4 SKEIIIFZ Fig. 2 Prior ArtBACKGROUND OF THE INVENTION The present invention relates to the fieldof the art where a source of molten material is solidified on amoving.heat-extracting member so as to form an elongated solid productonsuch a member. The prior art pertinent to the present invention wouldinclude US. Pat. application Ser. No. 251,985, assigned to a commonassignee, where a method of producing filamentary materials isdisclosed. In that reference there are no external forces applied to thefilament as it spontaneously leaves the rotating heatextracting memberand as a consequence the point of filament release varies somewhatduring the process. Similarly US. Pat. No. 2,825,108 discloses a methodof making filament by impinging a stream of molten material onto arapidly moving heat-extracting member. In both methods of filamentproduction the variations of the adhesion to the rotatingheat-extracting member made the release point unstable and as aconsequence both such processes have shortcomings that the presentinvention alleviates.

Surprisingly when-a tension force is applied to the filament and thefilament is supported, theinherently variable adhesion is overcome andthe release point stabilized without inducing breakage in the filamentdue to variations in tension. In addition, the applied force in thefilament does not interrupt the solidification of the filament on therotating heat-extracting member even though the tension force is appliedvery close to the point of filament solidification. This is especiallysignificant when it is realized the present invention operates at highrotational speeds and produces a small filamentary product.

One embodiment of the present invention also reduces filament breakageby controlling the rate of heat removal from the filament subsequent offormation from the melt thereby reducing filament embrittlement causedby solid state transformations dependent on the rate of heat removal.

It is one object of the present invention to stabilize the release pointof the filament from the rotating heatextracting member. In doing so thepresent invention alleviates numerous shortcomings of the aforementionedprior art methods. The present invention is applicable to prior artforming techniques that relay on spontaneous release of the filamentaryproduct from the rotating heat-extracting member.

When such release occurs, it is influenced by the speed'of the rotatingmember and the trajectory of the released filament is a function of thisspeed; As a result the collection of the filament is difficult since thecollecting means must be able to adapt to the different trajectoriesintroduced when the rotating member changes speeds. The presentinvention makes the trajectory of the'filament independent of the speedof rotation of the heat-extracting member, therefore, eliminating somecollection problems.

In addition, the two noted prior art processes introduce smallcross-section filaments into a gaseous atmosphere at high velocities.This results in the generation of aerodynamic forces on such filamentsthat tend to buckle the filamentinmid-air. Where the object of theprocess is to produce continuous filament, this buckling and theresultant tangling of the filament prevent collection of the filament ina usable form and thereby limits its use. The present invention reducesthe aero dynamic forces exerted-on the filament by having the filamentslide on'a support between the release point and the tension exertingmeans and therefore the filament may be collected in an orderly mannerthat was impossible with the prior art methods.

The sliding contact of the filament in contact with the support hasadditional benefits. First it limits the access of the surroundingatmosphere to the surface of the filament which reduces oxidation of thefilament. Second the support itself can be used to control the rate ofheat removal from the filament by manipulating the thermal capacity ofthe support means. In this manner materials that undergo embrittlingtransformations dependent on the rate of heat removal could be collectedwhere such an embrittlement would have ordinarily made such a filamentvirtually uncollectable.

The present invention not only improves the application of the prior arttechniques of producing continuous filament but makes such techniquespractical for the collection of continuous lengths of materialsheretofore considered unmanageably brittle if produced directly from themolten material.

I SUMMARY OF TI-IE'INVENTION The present invention is a methodrofstabilizing the release point of afilament producingmethod thatsolidifies a filamentary product on the surface of a rotatingheat-extracting member relying on spontaneous release of the fiber fromthe surface of the rotating member. By the application of a tensionforce to the filament subsequent to its release from the rotating memberwhile supporting the filament at a position lower than its free flighttrajectory the operation of the forming method is enhanced and problemsassociated with product collection and handling are reduced. The meansused to sup port the filament may also be used to control the rate ofheat removal from the filament subsequent to its release from therotating member by altering its thermal capacity.

The present invention would contemplate the application of a tensionforce to a filament subsequent to its release from a rotatingheat-extracting member and the supporting of such a filament on a memberbelow the free flight trajectory of 'such a filament leaving therotating member without the applied tension. The magnitude to thetension is less than other forces causing the release of the filamentfrom the rotating member and is sufficient only to overcome variationsin the adhesion of the filament to the rotating member with the filamentspontaneously-releasing from the rotating member with or without theapplication of the tension force.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partial cross section ofthe invention as it is used with one particular filament forming methodshowing the relationship between the process of filament formation andthe application of an aligned force through the filament.

FIG. 2 is a cross section of the circumferential edge of the rotatingmember of FIG. 1.

FIG. 3 is a partial cross section of the invention as it is used with asecond filament forming method showing the relationship of the freeflight trajectory to the path of the filament utilizing the presentinvention.

FIG. 4 is one embodiment of a means used to generate the tension forcein the filament.

DETAILED DESCRIPTION OF THE INVENTION The present invention is animprovement to processess forming continuous solid filament by at leastpartially solidifying molten material in filament form on a rotatingheat-extracting member where the filament is spontaneously released fromthe rotating member. The small tension and bending forces applied evento materials exhibiting little measurable ductility do not promotebreakage and product continuity is significantly easier with the presentinvention than with the cited prior art techniques involving spontaneousfilament release. The application of a directed tension force stabilizes the process of filament formation by inducing a constant releasepoint of the filament from the heatextracting member. The presentinvention is operable with extremely brittle materials in someembodiments and facilitates a constant release point without inducingfilament breakage.

FIG. 1 shows a cross-sectional view of one embodiment of the presentinvention. The rotating disk-like member 30 is in contact on itscircumferential edge 32 with the surface ofa pool of molten material 10.The final filament. is shown as being solidified on the circumferentialedge 32 as 20 and then leaving contact with the edge 32 at the releasepoint 21. The release point 21 is determined in part by theconfiguration of the guide member 50 and the force F applied through thefilament 20. The force F has two operative components. F is the tensioncomponent of the force F at the point 51 where the filament 20 beginscontact with the member 50 and F, the component normal to F at point 51keeping the filament in contact with the member 50.

While the application of a tension force F creates both F T and F, thetwo forces have two separate functions. F as applied through thefilament determines the location of the release point 21 and it is thestabilization of this release point that yields an improvement inoperation over the prior art. The normal force F as applied to themember 50 through the filament 20 keeps the filament 20 in contact withthe member 50. This contact maintains the geometric relationship of thetension force F that maintains the stability of the release point 21.

The contact of the filament 20 with a support member 50 between therelease of filament and the means used to apply the force F is anecessary element of the present invention. The application ofa tensionforce in the filament with the support produces an improvement infilament continuity.

In addition to the improvement in filament continuity provided by thepresent invention, the member 50 can be utilized to provide otherimprovement to the process.

Where the filament is prone to oxidation after formation, the contactwith the support member 50 shields one side of the filament from thegaseous atmosphere while reducing the access of the gas to the otherside by preventing unimpeded gas flow over the filament.

The member 50 may also be used as a means to control the rate of heatremoval from the filament subsequent to formation. Where the filamentmaterial undergoes a heat rate dependent solid state transformation (asfor example the martensitic reaction of carbon steel) the member 50 maybe heated so as to reduce the heat removal rate from the filament andthereby reduce the quenching effect of the atmosphere surrounding thefilament subsequent to its formation from the melt. In addition, thethermal capacity of the support member 50 may be used to control therate of heat removal from the filament. If it is desired to acceleratethe rate of heat removal from the filament, the support member wouldhave a high thermal capacity. Such a member could be a mass of materialhaving a high intrinsic heat capacity or a solid material artificiallycooled. Where it is desired to retard the rate of heat removal from thefilament, the support member would be heated thereby lowering itscapacity to remove heat fromthe filament in contact with it. It shouldbe understood that the term thermal capacity does not correspond to aspecific material property such as heat capacity or thermal conductivitybut is simply descriptive of the capacity of the support to alter thetemperature of the filament in contact with it by the transport of heat.

FIG. 2 shows a cross-sectional view of the circumferential edge of therotating member 30disposed to produce a filamentary product operablewith the present invention. The embodiment shown in FIG. 2 is from theprior art (US. Pat. application 251,985) and consists of a disk-likemember 30 having a V-shaped peripheral edge. The legs of the V 31 areangularly disposed on angle 0 with the tip of the V 32 (see FIG. 1)having a radius of curvature in the plane of the drawing in FIG. 2 of r.The V-shaped circumferential edge 32 is at a distance R from the axis ofrotation of the member 30 below the surface 15 of the melt 10.

A preferred embodiment of the present invention comprises theembodiments of FIGS. 1 and 2 to produce continuous filamentary materialwhen the member 30 is of the dimensions in the ranges:

Radius (R) from 2 to 10 inches Thickness (T) from 0.05 to 2 inches 0from 60 to 120 r from 0.005 to 0.10 inch v Such a member would berotated at a speed in excess of 3 feet per second and preferably lessthan 50 feet per second at the circumferential edge and would have adepth of insertion (d) into the melt 10 less than 60 mils below thesurface 15. The upper bound of the preferred rotational speed appears tobe the result of equipment limitations imposed by thehigh rotationalspeeds rather than an inherent limitation of the invention. It is withinthe skill of persons in the art of equipment design to devise rotatingmembers capable of greater circumferential speeds than is the upperbound of the preferred embodiment.

The present invention is also operable with other means of producingfilamentary material by solidifying molten material in the form of afilament on a rotating heat-extracting member. FIG. 3 depicts thepresent invention as used with a variant of the teachings of U.S. Pat.No. 2,825,108, Pond. The rotating heat-extracting member 30 is acylindrical disk-like member having a smooth outer radial surface 33. Aclosed container 40, with a source of gas pressure 43, is used to heat avolume of molten material by heating element 42 adjacent the containerwalls. An orifice 41 in the container 40 forms the molten material 10into a continuous filamentary shape 22 upon the application of the gaspressure. When the ejection velocity of the molten material from theorifice is substantially close to the linear velocity of the outerradial surface 33 of the rotating member 30,'a continuous product 241*is formed. Similar to the embodiment shown in FIG. 1 the adhesion of thefilament to the surface 33 is variable and as a result the release point21 is variable. As shown in FIG. 3 the trajectory of the filament 20without the application of the force F is indicated by the path 70.. Theapplication of the force F lowers the path of the filament 20 below itsequilibrium free flight trajectory 70 into sliding contact with thesupport member 50.

The present invention has been shown with two methods of producingcontinuous filamentary material but is not limited to those embodiments.The invention is applicable to any filament producing method where acontinuous solid filament is produced by the solidification of moltenmaterial on the surface of a moving heat-extracting member where suchfilament is spontaneously released from the surface without thenecessity of external forces to break the adhesion of the filament tothe surface.

By filamentary product, we mean that the product should have aneffective diameter less than about 60 mils. An effective diameter is away of defining the size of a filament having a cross section that maybe noncircular. A filament having an effective diameter of 60 mils has across-sectional area equal to a circular filament 60 mils in diameter.Therefore the present invention is operable with filament having largewidth-tothickness ratios commonly termed ribbon fiber.

The present invention is not inherently limited as to the speed at whichthe member 30 is rotated (which of course controls the linear productrate of filament) as long as the means used to generate the tensionforce F can do so at the operating speed. At normal production speeds wehave found that a synchronous carousel arrangement as depicted in FIG. 4is one operable embodiment that generates a self-regulating tensionforce of the required magnitude.

The member 60 rotates on a horizontal plane where the filament 20naturally exits the support 50. The member 60 is rotated at a continuousspeed having a vertical containment 61 at its outer radius. Theselfregulating force is generated by having this outer radius rotatingat a linear velocity in excess of the rate at which the filament 20 issupplied. The difference in rates is not known to be critical, however,this embodiment is known tobe operable where the linear velocity at thevertical containment is 100 percent greater than the input velocity ofthe filament. Upon initiation of the process the filament 20 travels byits free flight trajectory to impinge on the horizontal surface 65. Thissurface is relatively flat and the filament 20 will continue to travelon the surface 65 until it strikes the vertical containment 61. Therotation of the member 60 carries the filament around the circumferencebut in doing so places some portion of the filament 20 on a radius ofthe surface 65 where the linear velocity of the filament equals that ofthe surface 65 at impingement so as there is no relative motion betweenthe filament 20 and the surface 65. This radius is termed theequilibrium collection radius 62 on the turntable-like surface 65. inthis manner the filament is free to determine a radius on the surface 65without the need for precisely matched speeds of the collector to thefilament producing means or mechanical guidance of the filament to 6 theequilibrium collection radius 62. When the filament 20 is collected atsuch a radius, there is a force transrnitted to the filament'Zll thatdraws the filament into contact with the support member and stabilizesthe release point of the filament from the rotating heatextractingmember.

The only requirement of the tension applying means is that it produce alimited'and relatively constant pulling-force F of a specific magnitude.The exact tension required to utilize the benefits of the inventionqualitatively depends upon the system used, the radius of the member34), the size and composition of the filament, and the placement andshape of the support 56.

Quantitatively the magnitude of the force as applied at the releasepoint (P must conform to several relationships. The force that holds thefilament to the surface of the rotating member is composed of a minimumforce of adhesion F plus A the deviation of the adhesion force above thevalue of F It is the effect of the deviation A that makes the releasepoint vary in relation to the position on the rotating member. When thesystem is in equilibrium there are three major forces that operate tobreak the adhesion of the filament from the forming surface of therotating heat-extracting member. These three major forces havecomponents generating a shear force parallel to the forming surface anda normal component to that surface. Both shear and normal forces operateto release the filament from the forming surface, however, the normalforces also operate to move thefilament away from the forming surface.The first m'ajor'force is centrifugal force (F which is normal to theforming surface.

The magnitude of F, is dependent on the mass of the filament and thediameter and speed of the rotating member. The second force is then apredominantly shear force created by the differential thermalcontraction (F between the filament and the forming surface uponcooling. This force is parallel to the forming surface and is determinedby the difference between the thermal contraction of the materialscomprising the filament and the material comprising the forming surfaceat their respective operating temperatures. The third major force is thetension force (F exerted on the filament. Such a force would, dependingon the geometric relation of the tension tothe release point, have bothnormal (F and shear (F components. Further more the production ofcontinuous filament inherently generates a small force (F,,,) asevidenced by the fact that the free flight trajectory of discontinuousfilament is somewhat different thanthat of continuous filament. Theinherent force is believed to have a negligible shear component and iscomprised mainly of a force normal to the forming surface. This force isgenerated by the weight of thecontinuous filament not adherent to theforming surface nor supported by the member 50.

in summary, the forces operating to determine the release point are:

F A minimum force of adhesion of the filament to the forming surface Athe deviation of the adhesion force above the value of F F the forcenormal to the forming surface generated by centrifugal force on thefilament F the force parallel to the forming surface generated bydifferential thermal contraction F the induced tension in the filamenthaving both normal and shear components F the component of the tensionforce F normal to the forming surface F the component of the tensionforce F parallel to the forming surface F m the inherent force generatedwhen the product is continuous, normal to the forming surface it is theobject of the present invention .to use F to override the effect of A soas to stabilize the point of release of the filament from the formingsurface. The release of the filament from the forming surface isspontaneous with or without the application of F and therefore Thissimply means that where no external tension F is applied, centrifugalforce, differential thermal contraction, and the small inherent tensionforce are sufficient to induce filament release. The problem is that thevarying adhesion force F A makes the release point vary thereby inducinginstability to both filament production and collection.

When the external tension force F is applied the shear component F actsin conjunction with the other shear force F on the forming surface. Asthe tension force F is increased, the release point will move toward aposition on the forming surface minimizing the normal component F andunless the geometry is correct, the equilibrium position may be a pointprior to filament formation or at a point where the filament hasinsufficientstrength to withstand the tension. In a geometricconfiguration where F is applied through the filament so F is a tangentto forming surface at the release point, a significant tension may beexerted without moving the release point since there is no normal force(F to induce movement of the release point and the shear force (F doesnot initiate separation of the filament from the forming surface. Bycontrast when the normal component F is significant, the effect ofA isminimized and the release point is stabilized without the need ofexerting a large tension force F through the filament.

The application of the normal tension force F is not required to removethe filament from the formingsurface and such release is spontaneouswith or without the applied normal tension force. F does minimize theeffect of A and promotes stability of the release point. It follows thenthat:

FTII A While the absolute magnitudes of the forces are not known. therelative magnitudes can define the invention and one skilled in the artcan use the teachings of this disclosure and create an operableembodiment of the invention without undue experimentation.

It should be understood that F and A could be broken down into theirnormal and shear components, however, it is sufficient to describe thoseforces in general since the shear components do not change the point offilament release but merely reduce the adhesive bond so the normalforces can more readily affect the separation of the filament from theforming surface.

The member 50 determines the path of the filament 20 and therefore thedirection of the tension force F The presence of the support 50 iscritical to the present of the filament. While there is no indicationthat the following configuration is the only operable embodiment of theinvention, we have had particular success where the support member isbelow the free flight trajectory of the released filament andthe-tension force is applied so as to lower the path of the filamentonto the support member. It should also be possible to support thefilament above its free flight path, however, care must be taken toprevent the position of the support to generate a large normal force atthe release point so as to move the release point too far toward thearea of filament formation.

The embodiment illustrated in FIG. 3 is confined to metallic filamentand the embodiment illustrated in FlGS.. l and 2 is confined tomaterials having the following properties at a temperature within 25percent of their melting points in K: a viscosity in the range of from10 to l poise, a surface tension in the range of from 10 to 2000dynes/cm, a reasonably discrete melting point, and at least momentarycompatibility with a solid material having sufficient thermal capacityto initiate solidifieationFor'the purpose of definition a reasonablydiscrete melting point is in general where a material exhibits adiscontinuous increase in viscosity upon removal of heat from thematerial while in a molten state.

The present invention is not limited to specific materials found to becritical in the embodiments of the filament forming methods. The presentinvention is operable on any filamentary material formed bysolidification on a moving heat-extracting member.

The present invention has been shown to operate in the followingexamples.

EXAMPLE 1 The carousel arrangement of FIG. 4 was used to put a tensionon a continuous aluminum fiber produced by rotating abrassheat-extracting member of the general configuration of the priorart embodiment of FIG. 2 in contact with the surface of the moltenaluminum. The aluminum was commercially pure (1 100) aluminum at atemperature of approximately l400F. The rotating member had a V-shap'edcircumferential edge and a diameter of approximately 8 inches. Thecircumferential edge was in contact with the surface'of the moltenaluminum at a linear rate of approximately 15 feet per second. Afterrelease from the rotating member, the filament was supported below itsfree flight trajectory on a sheet metal support. The filament wasdirected by the support onto a turntable rotating so as to yield aradius having a velocity approximating that of the filament. Thefilament was collected on an equilibrium radius lowering the filamentonto the support member and continuous aluminum filament having aneffective diameter of 21 mils was produced for 30 minutes of operation.

EXAMPLE 2 The same tension-inducing embodiment used in the previousexample was used to produce continuous austenitic manganese (Hadfield)steel filament having a typical analysis of 11-13% Mn, l.01.3% C,O.70.3% Si, balance Fe. A nickel rotating heat-extracting member wasused having the V-shaped, circumferential edge of FIG. 2. The wheel was8 inches in diameter and was water cooled at a flow rate of gallons perhour. The forming surface had a peripheral speed of 5 feet per second.Lengths of steel fiber up to 900 feet long were produced having aneffective diameter of about 18 mils. The melt'temperature duringfilament formation was approximately 2800F.

EXAMPLE 3 Again the horizontal turntable embodiment was utilized toprovide tension to continuous filament. The filament produced was whitecast iron of a composition approximating 4.0% C, 0.8% Si, 0.7% Mn withthe balance essentially Fe. The final filament had little measurableductility and was extremely brittle. A copper wheel formed the filamentby contacting its V-shaped circumferential edge moving at approximately7 feet per second to the surface of the molten iron at 2670F. Thetension drew the filament down from its free flight trajectory intosliding contact with a support member and lengths of brittle cast ironfiber 50 feet long were collected on the tension inducing turntable. Thefilament had an effective diameter of l2 mils.

' EXAMPLE 4 As in the previous examples the horizontal turntable wasused to induce tension in the filamentary product. The filament producedwas a plain carbon mild steel (Type 1005) containing approximately 0.05%carbon, 0.2% Mn with the balance essentially iron. An aluminum disk witha V-shaped periferal edge was used to form the filament by contactingits acute angle with the surface of molten steel at 7 feet per second.The steel was at a temperature of approximately 2900F. Thefilament wasin sliding contact with a support below its free flight trajectory andcontinuous filament was collected on the turntable. The filament had aneffective diameter of 25 mils.

While the invention is disclosed in terms of specific embodiments andexamples, the scope of the invention is not limited thereto. Theinvention is known to be operable with additional metal alloys thanthose set out in the examples as for example the alloys of: copper,zinc, tin. nickel, and cobalt. The present invention was reduced topractice in numerous trials and the invention is operable as defined bythe appended claims and any unsuccessful trials were not felt to belimitations to the invention but were readily explained vagaries of thetechnology involved.

We claim:

1. In a method of forming filamentary material where said materialsolidifies in filament form adherent to a rotating heat extractingmember the improvement of:

stabilizing the release point of said filament from said rotatingheat-extractin g member by the application of a tension to said filamentwith said force drawing said filament into sliding contact with asupport member positioned between said release point and the location ofthe tension exerting means. 2. The method of claim I wherein saidrelease point is stabilized by the forces on said filament at itsrelease point conform to the following relations where (in units offorce) F A the minimum force of adhesion of said filament to said memberA the deviation of the adhesion force above the value F A F, thecentrifugal force exerted on said filament while adherent to said memberF,, the shear force exerted by differential thermal contraction at theinterface of said filament and said member at the release point F,, theinherent normal force due to the unsupported weight of the continuousfilament F the tension force exerted on said filament F the component ofF normal to the forming surface F the component of F parallel to theforming surface. I I

3. The method of claim 2 where said support member is below the freeflight trajectory of the released filament. l

4. The method of claim I where said filament is formed by forcing moltenmaterial through an orifice in the form of a free-standing stream ofmolten material and impinging said stream on the polished outer radialsurface of a cylindrical rotating heat-extracting member before surfacetension effects degrade said stream into a nonfilamentary form.

5. The method of claim 1 where said filament is formed by rotating theV-shaped outer radial surface of a disk-like heat-extracting member incontact with the surface of a pool of molten material at a rotationalspeed yielding a linear velocity at the circumference of said rotatingmember in excess of 3 ft/sec.

6. The method of claim 1 where the rate of heat removal from saidfilament subsequent to release from said rotating heat-extracting memberis controlled by the thermal capacity of said support member.

7. The method of claim 6 where the rate of heat removal is lowered byproviding a support with low ther mal capacity.

8. The method of claim 6 where the rate of heat removal is acceleratedby providing a support with high thermal capacity.

9. The method of claim 1 where said tension is exerted by directing saidfilament by means of said support member to the surface of a rotatinghorizontal turntable with said filament free to determine an equilibriumcollection radius. I

10. The method of claim 1 where said material has, at a temperaturewithin 25 percent of its equilibrium melting point in K, a viscosity inthe range from 10" to l poise, a surface tension in the range of from 10to 2000 dynes/cm, and a reasonably discrete melting point.

H1. The method of claim l where said material is a metal selected fromthe group consisting of the alloys of: iron, aluminum, copper, zinc,tin, nickel, and cobalt.

12. The method of claim 1 where said material is a metal alloy selectedfrom the group consisting of: l

1. In a method of forming filamentary material where said materialsolidifies in filament form adherent to a rotating heatextracting memberthe improvement of: stabilizing the release point of said filament fromsaid rotating heat-extracting member by the application of a tension tosaid filament with said force drawing said filament into sliding contactwith a support member positioned between said release point and thelocation of the tension exerting means.
 2. The method of claim 1 whereinsaid release point is stabilized by the forces on said filament at itsrelease point conform to the following relations FA + Delta < Fc + Fd +Fw + FT FT FTn + FTs Delta <<FTn where (in units of force) FA theminimum force of adhesion of said filament to said member Delta thedeviation of the adhesion force above the value FA Fc the centrifugalforce exerted on said filament while adherent to said member Fd theshear force exerted by differential thermal contraction at the interfaceof said filament and said member at the release point Fw the inherentnormal force due to the unsupported weight of the continuous filament FTthe tension force exerted on said filament FTn the component of FTnormal to the forming surface FTs the component of FT parallel to theforming surface.
 3. The method of claim 2 where said support member isbelow the free flight trajectory of the released filament.
 4. The methodof claim 1 where said filament is formed by forcing molten materialthrough an orifice in the form of a free-standing stream of moltenmaterial and impinging said stream on the polished outer radial surfaceof a cylindrical rotating heat-extracting member before surface tensioneffects degrade said stream into a nonfilamentary form.
 5. The method ofclaim 1 where said filament is formed by rotating the V-shaped outerradial surface of a disk-like heat-extracting member in contact with thesurface of a pool of molten material at a rotational speed yielding alinear velocity at the circumference of said rotating member in excessof 3 ft/sec.
 6. The method of claim 1 where the rate of heat removalfrom said filament subsequent to release from said rotatingheat-extracting member is controlled by the thermal capacity of saidsupport member.
 7. The method of claim 6 where the rate of heat removalis lowered by providing a support with low thermal capacity.
 8. Themethod of claim 6 where the rate of heat removal is accelerated byproviding a support with high thermal capacity.
 9. The method of claim 1where said tension is exerted by directing said filament by means ofsaid support member to the surface of a rotating horizontal turntablewith said filament free to determine an equilibrium collection radius.10. The method of claim 1 where said material has, at a temperaturewithin 25 percent of its equilibrium melting point in *K, a viscosity inthe range from 10 3 to 1 poise, a surface tension in the range of from10 to 2000 dynes/cm, and a reasonably discrete melting point.
 11. Themethod of claim 1 where said material is a metal selected from the groupconsisting of the alloys of: iron, aluminum, copper, zinc, tin, nickel,and cobalt.
 12. The method of claim 1 where said material is a metalalloy selected from the group consisting of: 1100 aluminum, white castiron, austenitic manganese steel, plain carbon mild steel.